eventfd: revised interface and cleanups

Change the eventfd interface to de-couple the eventfd memory context, from
the file pointer instance.

Without such change, there is no clean way to racely free handle the
POLLHUP event sent when the last instance of the file* goes away.  Also,
now the internal eventfd APIs are using the eventfd context instead of the
file*.

This patch is required by KVM's IRQfd code, which is still under
development.

Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Cc: Gregory Haskins <ghaskins@novell.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Avi Kivity <avi@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/include/linux/aio.h b/include/linux/aio.h
index b16a957030f8..47f7d932a01d 100644
--- a/include/linux/aio.h
+++ b/include/linux/aio.h
@@ -121,9 +121,9 @@ struct kiocb {
 
         /*
          * If the aio_resfd field of the userspace iocb is not zero,
-         * this is the underlying file* to deliver event to.
+         * this is the underlying eventfd context to deliver events to.
          */
-        struct file             *ki_eventfd;
+        struct eventfd_ctx      *ki_eventfd;
 };
 
 #define is_sync_kiocb(iocb)     ((iocb)->ki_key == KIOCB_SYNC_KEY)